Dropbox did confirm to Ars that it checks publicly shared file links against hashes of other files that have been previously subject to successful DMCA requests. “We sometimes receive DMCA notices to remove links on copyright grounds,” the company said in a statement provided to Ars. “When we receive these, we process them according to the law and disable the identified link. We have an automated system that then prevents other users from sharing the identical material using another Dropbox link. This is done by comparing file hashes.”

Dropbox added that this comparison happens when a public link to your file is created and that “we don’t look at the files in your private folders and are committed to keeping your stuff safe.”